Expert Working Groups

The analysis of recent airborne campaigns showed differences in cloud products (e.g., size distributions, bulk cloud properties) resulting from different data analysis methods of imaging cloud probes. Hence experts and students from 26 institutions participated in the EUFAR/IAMAS/IUGG/ICCP Workshop on Processing of Cloud Particle Measurements at German Aerospace Center (DLR) Oberpfaffenhofen to discuss, optimize and harmonize cloud data analysis in order to augment data quality of current optical array probes employed on aircraft. 39 participants from 12 nations met from 7 to 9 July 2017 at the Institute for Physics of the Atmosphere to receive training on cloud probe software and to transfer knowledge on cloud probe data evaluation within the international cloud community. The workshop was planned in connection with EUFAR’s 2nd International Conference on Airborne Research for the Environment (ICARE 2017) held at DLR in Oberpfaffenhofen, from 10 to 13 July 2017.

The workshop was planned as a follow-up to the 2014 Cloud Probe Intercomparison Workshop prior to the AMS cloud conference in Boston and the 2016 Cloud Probe Software Workshop prior to the International Conference on Clouds and Precipitation (ICCP) in Manchester. These two workshops set the stage for the 2017 workshop that focused on data analysis of optical array cloud probes and hands-on training with the most commonly used software packages by students and early career scientists who will be working with cloud measurements in the future. By the close of the workshop, participants were proficient in manipulating, analyzing and graphing cloud data.

The workshop opened on 7 July 2017 with introductions by Hans Volkert (DLR) for IAMAS/IUGG, Christiane Voigt (DLR) representing EUFAR and Darrel Baumgardner (DMT) for ICCP. Then Darrel Baumgardner presented an overview of sensors, their operating principles and limitations of single particle light scattering spectrometers. Thereafter, an overview of single particle imaging spectrometers and algorithms to process optical array probe data by Greg McFarquhar (U Illinois) showed methods for depth of field determination, out of focus particle corrections, particle reconstructions and shattering corrections. After lunch, basic data analysis methods and typical errors were presented by Darrel Baumgardner. These introductory talks set the stage for the scope of the workshop to provide overviews and hands-on training on the individual cloud probe software packages currently in use within the cloud community. The training on software packages started with an introduction to the SPEC processing software by Colin Gurganus (SPEC) and the Canadian D2G processing software by Alexei Korolev (ECCC).

The workshop continued on next day with hands-on training in two parallel sessions. The software developers Aaron Bansemer (NCAR, SODA) and Jonny Croisier (U Manchester, OASIS) trained on the SODA and OASIS packages in session I, while Joe Finlon (U Illinois) and Adam Majewski (U Wyoming) presented the University of Illinois and University of Wyoming software programs in session II. After lunch participants switched sessions to allow each to get an introduction to all four software packages. After a productive day, the participants were able to operate two to four of the different programs on their laptops limiting the need for further assistance. The day closed with an overview of the features of the EUFAR EGADS software and data depository by Matt Freer (DMT), which is planned as a future data base for cloud probe processing algorithms. In the evening, the participants visited Munich and enjoyed a social dinner at the famous Hofbräuhaus.

David Delene (U North Dakota) opened session III on Sunday with an introduction to the University of North Dakota processing package, ADPAA, and a description of the software depository created for airborne cloud instrumentation. Then the status of the AMS monograph on Ice Formation and Evolution in Clouds and Precipitation: Measurement and Modeling Challenges was presented by Darrel Baumgardner and an update on the EUFAR Handbook on Airborne Measurements for Environmental Research (Edt. Brenguier and Wendisch) was given by Christiane Voigt.

The final discussion and outlook was guided by Greg McFarquhar with the objectives to create a Steering Committee to oversee software evaluation and standardization, to enhance software availability and to encourage and facilitate software documentation. As an outcome of the workshop, there are plans to submit a joint research proposal to EUFAR/EU/NSF. This might include the formation of an international cooperation for cloud probe data analysis with a step by step instruction on cloud data analysis for two selected data sets of cloud measurements, as well as a simulated test data set. Results will be presented in a workshop preceding the AMS cloud conference in Vancouver, Canada in 2018. The encouraging workshop ended with a trip to the monastery Andechs.